1. Field of the Invention
This invention relates to motor driven compressor units of the type utilized in air-conditioning and refrigeration systems. In particular, the present invention relates to a compressor cylinder head and base of laminated construction with integral inlet and outlet ports and refrigerant flow passages.
2. Description of the Prior Art
In a hermetically sealed compressor, it is advantageous to utilize the refrigerant returning from the evaporator to cool the motor. The transfer of heat from the motor also serves to vaporize any liquid refrigerant present in the input from the evaporator. In this manner the operating efficiency of the motor driven compressor unit is increased.
The piston type compressor also has an inherent noise problem. Suction and discharge pulsations are created in the stream of refrigerant at frequencies in the audio range. These pulsations are conveyed through the compressor structure and hermetically sealed housing to the surrounding air where they produce an unacceptable rise in the ambient noise level. These pulsations have necessitated the addition of muffling devices to the compressor units.
In previous compressor units, the above-mentioned cooling, vaporizing and muffling functions were accomplished by providing cast bases between the motor and compressor. These cast bases were made from iron or similar materials and required extensive machining operations which added to the cost in order to achieve a proper fit between the base and compressor and the base and motor.
U.S. Pat. No. 2,823,850 entitled "Carrier for a Motor Compressor of a Refrigerating Machine" issued to R. Hintze disclosed an alternate construction for the base. A pair of sheet metal members were formed with the proper mounting holes and then soldered together to produce a base. In addition these members were also formed with inlet and outlet ports and dished regions providing passages for conducting refrigerant to and from the compressor. The dished regions also defined accumulator cavities wherein pulsations inherent in a piston type compressor tend to be dampened. However, present day designs and construction methods dictate further reductions in noise level while decreasing unit size. The present invention utilizes a construction form which provides an efficient muffling function in a relatively small size.